I. Field
The present disclosure relates generally to electronics, and more specifically to low noise amplifiers for multiband receivers.
II. Background
A wireless device (e.g., a cellular phone or a smartphone) in a wireless communication system may transmit and receive data for two-way communication. The wireless device may include a transmitter for data transmission and a receiver for data reception. For data transmission, the transmitter may modulate a radio frequency (RF) carrier signal with data to obtain a modulated RF signal, amplify the modulated RF signal to obtain an amplified RF signal having the proper output power level, and transmit the amplified RF signal via an antenna to a base station. For data reception, the receiver may obtain a received RF signal via the antenna and may amplify and process the received RF signal to recover data sent by the base station.
A wireless device may support operation over a wide frequency range. For example, the wireless device may support receiver (Rx) Carrier Aggregation (CA), which involves receiving an incoming RF signal that consists of an aggregate of two or more component carriers. The carrier aggregated RF signal needs to be down-converted using two or more distinct local oscillator (LO) frequencies, which typically requires a single input multiple out LNA for intra mode CA. Unfortunately, conventional LNA configurations utilize a large amount of circuit area and may suffer from degraded linearity.
It is desirable to have a dual stage low noise amplifier to support operation over a wide frequency range while reducing circuit area requirements over conventional LNAs and providing excellent linearity performance.